In early 1958, the 19-year-old moved to Spain where he would remain for the rest of his playing days, representing Deportivo de La Coruña for a couple of months then signing for Atlético Madrid.
He made his debut for the latter club on 14 September in a 2–0 home win against Real Oviedo, scoring the last goal;[1] three days later he was one four players netting braces in an 8–0 trouncing of Drumcondra F.C.
[2][3] During his nine-year spell at the Vicente Calderón Stadium, Mendonça would never appear in more than 25 La Liga matches, but was a solid attacking contributor as the Colchoneros won three Copa del Rey trophies and the 1962 UEFA Cup Winners' Cup, with the player scoring in the final's replay, a 3–0 victory over ACF Fiorentina.
[4] He left with competitive totals of 235 games and 91 goals,[3] retiring in June 1970 after unassuming top-flight spells with FC Barcelona (two seasons) and RCD Mallorca (one, team relegation).
FC Barcelona president Narcís de Carreras found this intolerable and ordered manager Salvador Artigas not to field him.